5-[4-(p-hydroxyphenoxy)phenyl]-5-oxo-3-methylvaleric acid



United States Patent 3,182,061 -[4-(p--HYDR0XYPHEN0XY)PHENYL]-5-0X0-3- METHYLVALERIC ACID Eric N. Goldschmidt, Hillside, N.J., assignor to Warner- Lamhert Pharmaceutical Company, Morris Plains, N.J.,

a corporation of Delaware No Drawing. Filed Mar. 20,1961, Ser. No. 96,719 1 Claim. (Cl. 260520) The present invention relates to 5-substituted derivatives of 5-oxo-3-methylvaleric acid having the formula:

El) CH3 wherein R is hydroxy, halo, lower alkoxy,

RFQO

in which R is lower alkoxy, hydroxy, nitro or amino and to a method of preparing these compounds.

The term lower alkoxy as used throughout the specification and in the claims refers to aliphatic groups containing 1 to 6 carbon atoms.

Exemplary of the compounds of this invention are Those compounds of my invention having the formula:

C-CH -fi-CH -COOH wherein R is a halo, lower alkoxy,

in which R; is lower alkoxy or nitro may be prepared by the following reaction:

AlCla Rsat-methylglutarlc anhydride ice The reaction is carried out in the presesnce of a molar excess of aluminum chloride in an anyhdrous inert solvent reaction medium, nitromethaue and methylene dichloride being particularly useful inert solvents. The reactants are agitated vigorously in the solvent and in the presence of aluminum chloride at a temperature of 5 C. or below for about 30 minutes to about 2 hours and the reaction is then brought to completion by refluxing for about 20 to about minutes or by maintaining the mixture at room temperature for periods up to about 3 days.

At the conclusion of the reaction, the mixture is treated with acid, extracted with ether and the product recovered from the extract by conventional techniques of crystallization, distillation or isolation in the form of crystallizable salts.

It has also been found that those compounds of the above formula where R is lower alkoxy, p-(lower alkoxy)phenyl or p-(lower alkoxy)phenoxy may be converted to 5 (p-hydroxyphenyl)-5-oxo-3-methylvaleric acid, 5 [4-(p-hydroxyphenyl)phenyl]-5-oxo-3-methylvaleric acid and 5-[4-(p-hydroxyphenoxy)phenyl]-5-oxo- 3-methylvaleric acid, respectively, by conventional dealkylation procedures. Treatment with aluminum chloride in methylene chloride under reflux, or 30 percent hydrobromic acid and glacial acetic acid, or potassium hydroxide in ethylene glycol under reflux are all eifective dealkylation procedures.

In addition, I have found that 5-[4-(p-nitrophenoxy) phenyl]-5-oxo-3-methylvaleric acid and 5-[4-(p-nitrophenyl)phenyl]-5-oxo-3-methylvaleric acid which may be prepared as described hereinabove by the reaction of 4-(p nitrophenoxy)benzene and 4-(p-nitrophenyl)benzene, respectively, with 3-methylglutaric anhydride, may be reduced by procedures conventionally employed to reduce an aromatic nitro group to an amino group, for example by treatment in alcohol with Raney nickel or palladium on barium sulfate to form 5-[4-(p-aminophenoxy)phenyl]-5oxo3-methylvaleric acid and 5 [4 (p-aminophenyl)phenyl] -5-oxo-3-methylvaleric acid, respectively.

The compounds of this invention are useful as chemical intermediates. The treatment of the compounds of this invention of the formula:

with a reducing medium comprising a suspension of zinc amalgam in acetic acid and concentrated hydrochloric acid, under reflux, results in the production of compounds of the formula:

wherein R is hydroxy, halo, lower alkoxy,

in which R is lower alkoxy, hydroxy or amino, as described in my application entitled Derivatives of 3- of this invention are unusually effective in blocking the conversion of acetyl Coenzyme A to cholesterol and its immediate precursors in this biosynthetic route. These compounds are thus valuable agents for use in the control of hypercholesteremia. In use, these compounds may be formulated with conventional pharmaceutical carriers to form dosage unit forms such as tablets, capsules, suppositories, solutions, suspensions and the like.

The following examples are included in order further to illustrate the present invention:

Example 1 To a suspension of 65.25 g. (0.49 mol) aluminum chloride in 600 cc. dry methylene chloride at room temperature is added, successively, a solution of 25 g. (0.195 mol) 3-methylglutaric anhydride in 50 ml. dry methylene chloride and 22.5 g. (0.2 mol) chlorobenzene in 50 ml. dry methylene chloride. This solution is stirred at room temperature for 16 hours. The reaction is halted by the slow addition of 120 ml. water, followed by 40 ml. concentrated hydrochloric acid, the temperature being held below 30 C. at all times. The solvent is then removed by steam distillation and the aqueous residue extracted with several portions of ether. The combined ether extracts are washed with water, dried over magnesium sulfate and the solvent removed. The residue is distilled and the fraction boiling at 148190 C./0.05 mm. of mercury is recrystallized from a mixture of 2 ethyl acetate in cyclohexane to give 5-(p-chlorophenyl)-5-oxo-3-methylvaleric acid, melting point=89.590.5 C.

Analysis:Calc.: C, 59.88; H, 5.44; Cl, 14.73. Found: C, 59.78; H, 5.52; Cl, 14.86

Example 2 Anisole and 3-methylglutaric anhydride are reacted with aluminum chloride in methylene dichloride as described in Example 1 The reaction conditions are two hours at C. followed by two hours at room temperature. The reaction is halted by the addition of 25 percent aqueous hydrochloric acid and the product isolated and crystallized as described in Example 1. Yield: 70 percent of theory of 5-(p-methoxyphenyl)5-oxo-3-methylvaleric acid, melting point 97-98 C.

Analysis:Calc.: C, 66.08; H, 6.83. Found: C, 66.05; H, 6.72.

Example 3 A suspension of 2.36 g. millimols) 5-(p-methoxyphenyl)-3-methyl-5-oxovaleric acid prepared as described in Example 3 and 6.65 g. (50 millimols) aluminum chloride in 50 m1. dry benzene is allowed to reflux for 4 hours. The reaction mixture is cooled and the reaction halted by the addition of cold dilute 1 N hydrochloric acid. The aqueous phase is extracted with ether, the combined organic phase dried and the solvent removed. The residue is recrystallized from hot water to yield 5-(p hydroxyphenyl)-5-oxo-3-rnethylvaleric acid in 80 percent yield, melting point=157158 C.

Analysis-Cale; C, 64.85; H, 6.35. Found: C, 64.82; H, 6.42.

Example 4 anisoTe without isolation of the intermediate 5-(p-methoxyphenyl)-5-oxo-3-methylvaleric acid.

Example 5 A mixture of p-nitrophenoxybenzene, 3-methylglutaric anhydride and aluminum chloride are reacted as described in Example 1 using nitromethane as the solvent. The reaction conditions are minutes at 0 C. followed by three days at room temperature. The reaction mixture is then processed in the manner described in Example 1 to yield crude 5-[4-(p-nitrophenoxy)phenyl]-5-oxo-3- methylvaleric acid.

This crude product is purified by adding an ethereal solution thereof to a freshly prepared ethereal solution of 2-benzyl-2-thiopseudourea. The precipitate which forms is crystallized from acetone to yield the 2-benzyl-2- thiopseudo-uronium salt of 5-[4-(p-nitrophenoxy)phenyl]-5-oxo-3-methylvaleric acid at 60 percent yield.

This salt is partitioned between ether and a phosphate buffer at a pH of 2-3. The ether is removed from the organic phase and the residue is recrystallized from carbon tetrachloride containing a small amount of ether to yield 5- [4- (p-nitrophenoxy) phenyl] -5-oxo-3-methylvaleric acid, melting point=81.5-82.5 C.

Analysis-Cale: C, 62.97; H, 4.99; N, 4.08. Found: C, 62.89; H, 5.18; N, 410.

Example 6 A solution of 5-[4-(p-nitrophenoxy)phenyl]-5-oxo-3- methylvaleric acid in percent aqueous ethanol is reduced at atmospheric temperature and room temperature with hydrogen over a 5 percent palladium-on-barium sulphate catalyst. When the theoretical amount of hydrogen has been taken up, the addition of hydrogen is stopped, the catalyst removed by fitlration and the solvent is evaporated. The residue is dissolved in methylene chloride and the resulting solution is treated with anhydrous HCl to give at a 67.5 percent yield the hydrochloride salt of 5-[4-(p-aminophenoxy)phenyl]-5-oxo-3- methylvaleric acid, melting p0int=157159 C.

Analysis.-Calc.: C, 61.80; H, 5.76; N, 4.00; Cl, 10.14. Found: C, 62.13; H, 6.04; N, 3.86; Cl, 10.13.

The same product is obtained by the reduction of 5-[4- ('p-nitrophenoxy)phe-nyl]-5-oxo-3-methylvaleric acid at room temperature and three atmospheres hydrogen pressure over a Raney nickel catalyst. The hydrochloride salt is purified by recrystallization from methanol containing a small amount of ether.

Example 7 p-Methoxyphenoxybenzene and 3-methylglutaric anhydride are reacted with aluminum chloride in methylene dichloride as described in Example 1. The crude product, isolated as described in Example 1, is distilled. The fraction coming over at 190240 C. at 0.1 mm. of mercury is recrystallized from 50-50 cyclohexanebenzene to give at a 30 percent yield 5-[4-p-methoxyphenoxy)- phenyl]-5oxo-3-methylvaleric acid, melting point=88 89 C.

Analysis.-Calc.: C, 69.50; H, 6.14. Found: C, 69.62; H, 6.25.

Example 8 A solution of 40 millimols 5-[4-(p-methoxyphenoxy)- phenyl]-5-oxo-3-methylvaleric acid in 80 glacial acetic acid and 80 ml. 48 percent aqueous hydrobromic acid is refluxed for 2 hours. The cooled mixture is poured into ml. Water. The solids are recovered and recrystallized from benzene to give at a 70 percent yield 5 [4 (p hydroxyphenoxy)phenyl] 5 0x0 3- methylvaleric acid, melting point=l18-l24 C.

Analysis.--Calc.: C, 68.78; H, 5.77. Found: C, 68.63; H, 5.90. I

-It is understood that the foregoing detailed decription is given merely -by way of illustration and that many variations may be made therein without departing from the spirit of my invention.

Having described my invention, what I desire to secure by Letters Patent is:

3,182,061 5 6 5 [4 (p hydroxyphenoxy)phenyl] 5 0x0 3- OTHER REFERENCES methylvalerw Fieser et. a1.: J. Am. Chem. $00., vol. 70 1948 pages 3200-3201.

Huang-Minton: I. Am. Chem. Soc., vol. 68, pp. 5 2487-2488 (1946).

References Cited by the Examiner UNITED STATES PATENTS 2,071,496 2/37 Bruson et a1. 260-415 LORRAINE WEINBERGIEIR3 2,792,418 5/57 Druey et a1, 260--520 Acting Primary Examiner- 3,038,034

6/62 Kerwin 260-520 X LEON ZITVER, CHARLES B. PARKER, Examiners. 

